JP2012168083A - Ac power source polarity switching device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an AC power source polarity switching device capable of automatically matching a polarity of an AC power source without requiring user's labor.SOLUTION: When a user comes into contact with a human body contact part 51 of a main power source switch 50 of electrical equipment B and a main power source is turned on, a polarity switching circuit 21 starts polarity switching by control of a polarity switch control circuit 22. A voltage measurement circuit 23 measures the voltage between a power source GND line 71 of a power source current supply line 70 and the earth 80 at least twice, namely before the polarity switching and after the polarity switching. The polarity switch control circuit 22 compares the voltage after the polarity switching measured by the voltage measurement circuit 23 with the voltage before the polarity switching stored in a storage part 24 and controls such that the polarity switching circuit 21 is switched to the polarity of the lower voltage, and notifies the user that a polarity setting has been normally completed through a notification part 25.

Description

  The present invention converts an AC power supply current input from an AC plug inserted into an outlet into a DC power supply current and supplies it to a circuit board via a power supply current supply line and a main power switch. The present invention relates to an AC power supply polarity switching device provided.

  Conventionally, as a method of identifying the earth ground of a household outlet of an AC power supply, the left side of the outlet is normally the earth ground or the left and right lengths of the outlet of the outlet from the rule of indoor wiring work. However, if there is a mistake in construction, etc., it will be used with the polarity reversed.

  By the way, many electrical devices such as audio devices in recent years are designed with the earth ground polarity of the input commercial AC power supply conscious. If the power supply ground is not connected as intended, the current flow in the device will deteriorate, causing deterioration in sound quality, producing a sound with no sharpness, or a sense of distortion in the sound, In many cases, the sound quality is poor because the localization is not clear.

  Therefore, when installing audio equipment, plug the outlet in accordance with the polarity indication mark on the plug of the device, and if the audio equipment does not have the polarity indication mark, use an AC voltage tester etc. The voltage of the ground and the earth ground was measured, and the earth ground polarity of the AC power supply was matched.

  Also, if the user extends the outlet with an extension cord, etc., the polarity display mark on the extension cord must be consciously inserted into the plug. The position of earth earth polarity was identified by the electric appliance.

  In order to solve such a problem, for example, an AC power supply earth polarity automatic selection device that automatically switches the earth ground polarity of an AC power supply has been proposed (see, for example, Patent Document 1).

JP-A-4-165923

  However, although it is possible to match the earth ground polarity of the AC power supply using an AC voltage tester, a voltage detector, or the like, there is a problem that it may not be implemented easily because it requires user effort. In addition, there is a problem that the user who has no knowledge about the earth ground polarity of the AC power supply is hardly implemented.

  In addition, even with the power source earth polarity automatic selection device described in Patent Document 1 described above, the earth earth polarity can be automatically switched, but the frame earth of the device is being supplied to the earth earth. Alternatively, when the outlet and the plug have a three-pole terminal, it is assumed that the plug is implemented by connecting the ground of the three-pole terminal plug to the ground output from the outlet. Therefore, for example, if the audio device uses a rubber insulator or the like to suppress vibrations, the frame ground of the device is not supplied to the earth ground only by placing the device, and also at the three-pole terminal The GND line is not always connected to earth ground due to a mistake in construction. Therefore, this also does not operate normally unless the user cares about it, and it takes time and effort from the user.

  Further, in the automatic power source polarity selection device described in the above-mentioned Patent Document 1, there is a problem that even if the polarity of the AC power source automatically changes, it is not known from the user side whether the polarity has actually changed. .

  Therefore, the present invention has been made to solve these problems, and it is an object of the present invention to provide an AC power supply polarity switching device that can automatically match the polarity of an AC power supply without requiring user effort. And

  In order to solve the above-mentioned problems, a first feature of the AC power supply polarity switching device according to the present invention is that a current based on an input AC power supply current is converted into a DC power supply current to supply a power supply current supply line (70) and a main power supply. A power supply circuit (40) to be supplied to the circuit board (60) through the switch (50), a polarity switching unit (21) for switching the polarity of the input AC power supply, and a power supply for the power supply current supply line (70) When the voltage measuring unit (23) that measures the voltage between the GND line (71) and the human body contact unit (51) provided in the main power switch (50) and the main power switch (50) are turned on. A storage unit (24) for storing the voltage measured by the voltage measurement unit (23); and the polarity switching after the storage unit (24) stores the voltage measured by the voltage measurement unit (23). Department ( 1), the polarity of the AC power source is switched, and then the voltage measuring unit (23) of the power source GND line (71) of the power source current supply line (70) after the polarity switching and the main power switch (50) are switched. The voltage between the human body contact part (51) is measured, the magnitude of the voltage after the polarity switching is compared with the voltage before the polarity switching stored in the storage part (24), and the storage part ( If the voltage before polarity switching stored in 24) is smaller than the voltage after polarity switching, the polarity switching of the AC power supply is further performed so that the polarity switching unit (21) switches the polarity of the AC power supply. And a polarity switching control unit (22) to be controlled.

  A second feature of the AC power supply polarity switching device according to the present invention is that the AC power supply polarity switching device transforms the input AC power supply into a power supply voltage corresponding to the electrical device (30). And the current converted by the power supply circuit (40) is an AC power supply current transformed by the internal transformer (30).

  Further, a third feature of the AC power supply polarity switching device according to the present invention is that, in the AC power supply polarity switching device, when the polarity switching control unit (22) executes control of polarity switching of the AC power supply, Informing the user through the notification unit (25) that the polarity switching control of the AC power source has been executed.

  A fourth feature of the AC power supply polarity switching device according to the present invention is that, in the AC power supply polarity switching device, the input AC power supply current is input from an AC plug (10) inserted into an outlet (104). The AC power supply polarity switching device further includes an AC plug insertion / removal detection unit (26) for detecting insertion / removal of the AC plug (10) with respect to the outlet (104), and the polarity switching control unit (22), the AC plug insertion / removal detection unit (26) detects that the AC plug (10) has been removed from the outlet (104), and then the AC plug (10) is connected to the outlet (104). When it is detected that the control of polarity switching of the AC power source has not been executed, the notification unit (25) informs the user that it has been detected. To knowledge, it lies in the fact.

  According to the AC power supply polarity switching device according to the present invention, when AC power is supplied to an audio device or the like from a home outlet, even if the polarity of the outlet at home is wrong or the user does not have knowledge about the power polarity, It is possible to automatically adjust the polarity of the power supply simply by turning it on.

It is a block diagram which shows the structural example of Example 1 of the alternating current power supply polarity switching apparatus based on this invention. It is a flowchart which shows the operation example of Example 1 of the alternating current power supply polarity switching apparatus based on this invention. It is a block diagram which shows the structural example of Example 2 of the alternating current power supply polarity switching apparatus which concerns on this invention. It is a flowchart which shows the operation example of Example 2 of the alternating current power supply polarity switching apparatus based on this invention.

  Embodiments 1 and 2 of the AC power supply polarity switching device according to the present invention will be described below. In the following description, as an electric device provided with the AC power supply polarity switching device according to the present invention, an AC power supply current input from an AC plug inserted into an outlet is transformed to a power supply voltage corresponding to the electric device by an internal transformer. Then, an audio device that converts the transformed AC power supply current into a DC power supply current by the power supply circuit and supplies the DC power supply current to the circuit board via the power supply current supply line and the main power switch will be described as an example.

  Many electrical devices such as audio devices are designed in consideration of the polarity of the ground (GND) of the AC power supply. Therefore, by introducing the AC power supply polarity switching device according to the present invention for audio equipment that is greatly affected by the polarity of the AC power supply, the user can automatically switch the polarity of the AC power supply without trouble. The sound quality intended by the person can be provided. However, the AC power supply polarity switching device according to the present invention is not limited to audio equipment, and may of course be applied to other electrical equipment.

  Hereinafter, an AC power supply polarity switching device according to a first embodiment of the present invention will be described in detail with reference to the drawings.

  In the AC power supply polarity switching device according to the first embodiment, when the user presses the switch of the main power supply of the audio device, the user's human body and the earth ground are connected, and the voltage between the internal circuit ground (GND) and the earth ground is measured. Then, after notifying the user of the completion of the polarity switching process by means of an LED display unit or a liquid crystal display, the user releases the main power switch so that the polarity switching is terminated at the same time as the power is turned on.

  FIG. 1 is a block diagram showing a configuration example of Embodiment 1 of an AC power supply polarity switching device according to the present invention.

  In FIG. 1, first, a pole transformer 101, an integrating wattmeter 102, a no-fuse breaker 103, an outlet 104, and the like are provided on the home A side.

  In FIG. 1, on the electric device B side such as an audio device, an AC plug 10, an AC power polarity switching device 20 according to the first embodiment, an internal transformer 30, a power circuit 40, a main power switch 50, Circuit board 60.

  The internal transformer 30 transforms an AC power supply current via the polarity switching circuit 21 of the AC power supply polarity switching device 20.

  The power supply circuit 40 converts the AC power supply current transformed by the internal transformer 30 into a DC power supply current having a predetermined voltage corresponding to the circuit board 60 of the electric device B, and supplies the circuit board 60 via the power supply current supply line 70. The circuit to be supplied includes a rectifier circuit 41 and a constant voltage circuit 42.

  The main power switch 50 is provided on the power supply current supply line 70, and the user controls the supply or stop of the DC power supply current to the circuit board 60 by turning on or off the main power switch 50. The human body contact portion 51 is provided on the main power switch 50. Specifically, the human body contact portion 51 is provided at a position to be touched when the user turns on or off the main power switch 50. In order to ensure the safety of the human body, the human body contact portion 51 is electrically insulated from the plus-side power supply current supply line 72 of the power supply current supply line 70.

  The circuit board 60 is a circuit board on which electronic / electrical circuits such as control circuits and operation circuits of the electric equipment B such as audio equipment are mounted.

  The AC power supply polarity switching device 20 according to the first embodiment includes a polarity switching circuit 21, a polarity switching control circuit 22, a voltage measurement circuit 23, a storage unit 24, a notification unit 25, and the like.

  The polarity switching circuit 21 switches the polarity of the AC power input from the AC plug 10 inserted into the outlet 104.

  The polarity switching control circuit 22 causes the polarity switching unit 21 to switch the polarity of the AC power supply. The polarity switching control circuit 22 supplies the voltage measuring circuit 23 with a power supply GND line 71 that is a negative output terminal of the power supply circuit 40 before polarity switching or a negative power supply current supply line of the power supply current supply line 70, and the main power switch 50. When the user touches the human body contact portion 51, the voltage between the user and the earth ground 80 via the user's human body and the same voltage after the polarity switching are measured. The magnitude of the same voltage after the polarity switching and the same voltage before the polarity switching stored in the storage unit 24 are compared. Then, only when the same voltage before polarity switching stored in the storage unit 24 is smaller than the same voltage after polarity switching measured by the AC voltage measuring unit 23, the polarity switching circuit 21 further switches the polarity of the AC power supply. Thus, the polarity switching of the AC power supply is controlled. That is, the polarity switching circuit 21 switches the polarity by the control of the polarity switching control circuit 22 while the user touches the human body contact portion 51 of the main power switch 50 of the electric device B and turns on the main power. The voltage measurement circuit 23 measures and compares the voltage between the power supply GND line 71 and the earth ground 80 at least twice before and after polarity switching. Then, the polarity switching control circuit 22 controls the polarity switching circuit 21 so as to switch to the polarity with the smaller voltage. Here, the polarity switching control circuit 22 sets the power source polarity of the AC power supply to the polarity of the smaller voltage of the same voltages before and after polarity switching. This is because the voltage between the negative output end of the power supply circuit 40 or the power supply GND line 71 of the power supply current supply line 70 and the human body contact portion 51 of the main power switch 50 and the earth ground 80 via the human body is small. This is because the polarity of the ground (GND) of the AC power source, that is, the power source polarity of the AC plug 10 can be correctly matched.

  Based on the control signal from the polarity switching control circuit 22, the voltage measuring circuit 23 performs the minus side output terminal of the power circuit 40 or the minus side power source of the power current supply line 70 twice before and after polarity switching. A voltage is measured between the power supply GND line 71 that is a current supply line and the earth ground 80 via the user's human body when the user touches the human body contact portion 51 of the main power switch 50. That is, in Example 1, while the user touches the human body contact portion 51 of the main power switch 50 of the electric device B and turns on the main power, the polarity switching circuit 21 switches the polarity of the AC power, The voltage measurement circuit 23 measures the voltage at least twice before and after polarity switching of the AC power supply.

  The storage unit 24 stores the voltage before the polarity switching measured by the AC voltage measurement unit 23, and is stored in a non-volatile memory, a volatile memory backed up by a backup power source, a battery (battery), or the like. It is configured.

  The notification unit 25 notifies the fact that the polarity switching of the AC power source according to the first embodiment has been correctly performed by turning on the LED, displaying a message, and further sounding a warning sound, and the like. The LED display unit and the liquid crystal display unit And an audio output circuit.

  Next, the operation of the AC power supply polarity switching device according to the first embodiment configured as described above will be described.

  First, as shown in FIG. 1, the user inserts the AC plug 10 into the outlet 104. Then, a nominal 6600V AC power supply current is transformed into 100V or 200V AC power supply current by the pole transformer 101, and the integrated wattmeter 102, no-fuse breaker 103, outlet 104, AC plug 10, and fuse 112 are used. And supplied to the polarity switching circuit 21 of the AC power source polarity switching device 20 according to the present invention.

  The polarity switching circuit 21 first sends an AC power supply current before polarity switching, which is an initial polarity state, to the internal transformer 30.

  The internal transformer 30 transforms the voltage of the AC power supply current before the polarity switching, which is the initial polarity state via the polarity switching circuit 21, to a predetermined voltage suitable for the working voltage on the circuit board 60 of the electric device B, To the B power supply circuit 40.

  In the power supply circuit 40, first, the rectifier circuit 41 rectifies the AC power supply current transformed to a predetermined voltage suitable for the circuit board 60 of the electric device B by the internal transformer 30 into a so-called pulsating voltage DC current. Next, the constant voltage circuit 42 converts the DC current of the pulsating voltage into a constant voltage, converts it into a DC power supply current, and outputs it to the power supply current supply line 70. However, in this state, the user does not touch the human body contact portion 51 of the main power switch 50 and the DC power source current is not supplied to the circuit board 60 via the power current supply line 70 and the main power switch 50. To do.

  Then, the user touches the human body contact portion 51 of the main power switch 50 to turn it on. Then, a DC power supply current of a predetermined constant voltage is supplied to the circuit board 60 via the power supply current supply line 70 and the main power supply switch 50, and the power supply of the electric device B is input. Up to this point, the operation is the same as that in the normal electric device B except that the AC power supply current is supplied via the polarity switching circuit 21.

  Next, the operation of the AC power supply polarity switching device 20 according to the first embodiment with the AC power supply polarity will be described with reference to the flowchart of FIG.

  First, the user touches the human body contact portion 51 of the main power switch 50 of the electric device B to turn on the main power switch 50. Then, the same voltage as the DC power supply current having a predetermined voltage supplied to the circuit board 60 is applied to the polarity switching start signal line 73. Then, the AC power supply polarity switching device 20 according to the first embodiment is turned on based on the voltage application to the polarity switching start signal line 73, and the polarity switching processing according to the first embodiment is started (S100). In the first embodiment, there are two polarity switching start signal lines 73 as shown in FIG. 1, that is, the + side line of the power supply current supply line 70 between the constant voltage circuit 42 and the main power switch 50. The power supply current supply line 70 between the main power switch 50 and the circuit board 60 is pulled from the + side line to the AC power supply polarity switching device 20. From these two polarity switching start signal lines 73, the AC power polarity switching device 20 can identify whether the AC plug 10 is inserted or removed or whether the main power switch 50 is turned on or off by a user operation.

  Specifically, in the AC power supply polarity switching device 20 according to the first embodiment, the polarity switching control circuit 22 controls the AC power supply polarity switching operation, and the polarity switching control circuit 22 first resets the storage unit 24 ( S110).

  Here, the user turns on the main power switch 50 of the electric device B. Thereby, since the user touches and turns on the human body contact portion 51 of the main power switch 50 of the electric device B, the user's human body touches the human body contact portion 51 and the voltage is passed through the human body contact portion 51 and the human body. The measurement circuit 23 is connected to the earth ground 80.

  Therefore, the voltage measurement circuit 23 includes a power GND line 71 that is a negative power supply current supply line of the power supply current supply line 70 supplied to the circuit board 60 of the electrical device B, the human body contact portion 51 of the main power switch 50, and the human body. The voltage between the ground and the earth ground 80 is measured (S130).

  The polarity switching control circuit 22 determines whether or not there is a problem in voltage measurement, such as whether the voltage measurement circuit 23 correctly measures the voltage between the power supply GND line 71 of the power supply current supply line 70 and the earth ground 80. Is determined (S140).

  Here, for example, because the human body is not touching the human body contact portion 51 of the main power switch 50, the voltage measurement circuit 23 determines the voltage between the power GND line 71 of the power current supply line 70 and the earth ground 80. If the measurement cannot be performed or if the human body does not correctly contact the earth ground 80 and does not measure the voltage correctly (S140 “problem”), the process proceeds to S150. Then, a control signal is output so as to output an error display or sound to the notification unit 25, and the user is prompted to turn on the main power switch 50 again. Then, the process returns to S100.

  In contrast, the polarity switching control circuit 22 determines that the voltage measurement circuit 23 correctly measured the voltage before the polarity switching between the power supply GND line 71 of the power supply current supply line 70 and the earth ground 80 (S140). “No problem”), the process proceeds to S160. Then, the voltage before polarity switching and the direction of polarity switching in the polarity switching circuit 21 are stored in the storage unit 24 (S160). Here, it is essential for the storage unit 24 to store the voltage before polarity switching, but it is optional to store the polarity switching direction in the polarity switching circuit 21, and the polarity switching direction in the polarity switching circuit 21. Of course, it is not necessary to memorize. If the storage unit 24 is a non-volatile memory, a backup power source or a battery (battery) is not necessary, but if the storage unit 24 is a volatile memory, the power source is a backup power source or a battery (battery). Remember that the contents of the memory will not be erased even if it falls.

  Next, the polarity switching control circuit 22 sends a polarity switching control signal to the polarity switching circuit 21 to control the polarity switching circuit 21 so that the AC power supply polarity in the initial polarity state is opposite to the polarity in the initial polarity state. (S170). That is, the polarity switching circuit 21 reverses the alternating power supply current positive and negative from the AC plug 10 and outputs it to the internal transformer 30.

  Next, the polarity switching control circuit 22 sends a voltage measurement control signal to the voltage measurement circuit 23 in the reverse polarity state. The voltage measurement circuit 23 again determines the voltage between the power supply GND line 71 of the power supply current supply line 70 and the human body contact portion 51 of the main power switch 50 and the earth ground 80 via the human body, that is, the reverse after polarity switching. The voltage in the polar state is measured (S180).

  Then, the polarity switching control circuit 22 compares the voltage after polarity switching measured by the voltage measuring circuit 23 in the reverse polarity state with the voltage before polarity switching stored in the storage unit 24 in the initial polarity state. . It is determined whether the voltage before polarity switching is equal to or higher than the voltage after polarity switching (S190). Here, when the polarity switching control circuit 22 determines that the same voltage before polarity switching stored in the storage unit 24 is smaller than the same voltage after polarity switching (S190 “No”), the polarity switching is performed. A polarity switching control signal is sent to the circuit 21 to control the polarity switching circuit 21 to switch the AC power supply polarity in the reverse polarity state to the polarity before the polarity switching in the initial polarity state (S200). As a result, the AC power supply polarity in the polarity switching circuit 21 returns to the initial initial polarity state.

  On the other hand, when the polarity switching control circuit 22 determines that the same voltage before polarity switching stored in the storage unit 24 is equal to or higher than the same voltage after polarity switching (S190 “Yes”), the process proceeds to S200. The process proceeds to S210 without executing the polarity switching process.

  In S210, the polarity switching control circuit 22 outputs a control signal to the notification unit 25 such as an LED display unit or a liquid crystal display, and outputs a message display or voice output that the polarity switching has been completed successfully. The user is notified (S210). Thus, the polarity switching operation of the AC power supply is completed (S220).

  Since it is assumed that a human body is in contact with the human body contact unit 106 during polarity switching, the polarity switching control circuit 22 prompts the notification unit 25 to be careful not to separate the human body from the human body contact unit 51. For example, in the case of an LED display unit or a liquid crystal display unit, it is preferable to perform blinking during polarity switching, or display such as turning on or off after the switching is completed. In addition, if the notification unit 25 is an audio output circuit, a warning sound may be output when released without permission in order to urge attention not to separate the human body from the human body contact unit 51.

  Therefore, according to the AC power supply polarity switching device 20 of the first embodiment, the polarity is switched while the user touches the human body contact portion 51 of the main power switch 50 of the electric device B such as an audio device and turns on the main power. The polarity switching circuit 21 switches the polarity under the control of the control circuit 22, and the voltage measurement circuit 23 at least twice before the polarity switching and after the polarity switching, the ground via the power supply GND line 71, the human body contact portion 51 and the human body. Measure and compare voltage to ground 80. Then, the polarity switching circuit 21 is switched to the polarity with the smaller voltage. As a result, even if the polarity of the outlet 104 on the home A side is wrong or the user does not have knowledge about the power polarity, the power polarity is automatically set by simply touching the human body contact portion 51 of the main power switch 50 and turning on the power. It becomes possible to match.

  As a result, if the electric device B is an audio device, the polarity of the AC power source as intended by the designer is ensured without requiring the user's trouble, and the cause of the deterioration of the sound quality is removed. The sound quality of the street can be reproduced. In addition, the human body contact portion 51 is provided on the main power switch 50, and the polarity switching control is executed when the main power switch 50 is turned on. Therefore, the user only performs the polarity switching control. No need for trouble.

  Next, the AC power supply polarity switching device 20 'according to the second embodiment of the present invention will be described.

  FIG. 3 is a block diagram illustrating a configuration example of the AC power supply polarity switching device 20 ′ according to the second embodiment.

  In FIG. 3, the AC power supply polarity switching device 20 'according to the second embodiment further adds an AC plug insertion / removal detection circuit 26 to the AC power supply polarity switching device 20 according to the first embodiment shown in FIG. Further, the AC power supply polarity switching device 20 'is obtained by adding a polarity switching notification function when the AC plug 10 is inserted / removed to the polarity switching control circuit 22' in addition to the function of the polarity switching control circuit 22 of the first embodiment. The other configuration is the same as that of the AC power supply polarity switching device 20 of the first embodiment.

  Here, differences from the configuration of the AC power supply polarity switching device 20 according to the first embodiment will be described. The AC plug insertion / removal detection circuit 26, for example, flows through the polarity switching start signal line 73, detects the insertion / removal of the AC plug 10 based on the change in the DC power supply voltage supplied to the circuit board 60 of the electric device B, and sets the detection result to the polarity This is notified to the switching control circuit 22 ′.

  The polarity switching control circuit 22 'performs polarity switching in the same manner as the AC power source polarity switching device 20 of the first embodiment. Further, after the polarity switching process, the polarity switching control circuit 22 'is notified from the AC plug insertion / removal detection circuit 26 that the AC plug 10 has been inserted / removed while the main power switch 50 is on. In this case, the user is notified through the notification unit 25 so that the polarity switching process is performed again. Note that the polarity switching control circuit 22 ′ touches the human body contact portion 51 of the main power switch 50 to turn on the power of the electric device B in order to make the user surely execute the polarity switching process at the time of the notification. To inform. Thereby, the polarity switching process of the first embodiment is surely performed.

  As described above, in the first and second embodiments, the AC plug insertion / removal detection circuit 26 is added, and in addition to the function of the polarity switching control circuit 22 of the first embodiment, the AC plug 10 insertion / removal is added to the polarity switching control circuit 22 ′. The difference is that a polarity switching notification function is added. Hereinafter, operations unique to the second embodiment will be described.

  FIG. 4 is a flowchart illustrating the polarity switching notification operation when the AC plug 10 is inserted / removed in the AC power supply polarity switching device 20 'according to the second embodiment.

  The operation when the AC plug 10 is inserted and removed in the AC power supply polarity switching device 20 ′ of the second embodiment shown in FIG. 4 is the AC power supply polarity switching processing by the AC power supply polarity switching device 20 of the first embodiment shown in FIG. This is an operation to be executed later.

  First, in the AC power supply polarity switching device 20 ′ of the second embodiment, the AC power supply polarity switching processing similar to that of the AC power supply polarity switching device 20 of the first embodiment shown in FIG. 2 is ended (S <b> 400). Thereafter, under the control of the polarity switching control circuit 22 ′, the AC plug insertion / removal detection circuit 26 detects a change in the DC power supply voltage supplied to the circuit board 60 of the electrical device B via, for example, the polarity switching start signal line 73 ( S410). The AC plug insertion / removal detection circuit 26 determines whether or not the power supply voltage has changed, that is, whether or not the AC plug 10 is not removed (S420). The AC plug insertion / removal detection circuit 26 only needs to be able to detect the removal of the AC plug 10 from the outlet 104. Therefore, the AC plug insertion / extraction detection circuit 26 may detect a change in the DC power supply voltage supplied to the circuit board 60 of the electric device B via the polarity switching start signal line 73. Of course, the AC plug insertion / removal detection circuit 26 may detect the removal of the AC plug 10 by detecting a change in the power supply voltage in the AC plug 10, the internal transformer 30, the power supply circuit 40, or the like.

  Here, when the AC plug 10 is removed from the outlet 104 after the automatic AC power polarity switching operation similar to that of the AC power polarity switching device 20 of the first embodiment shown in FIG. Disappears. As a result, the AC power supply current transformed by the internal transformer 30 is not input to the power supply circuit 40, and the DC power supply current is also supplied from the power supply circuit 40 to the circuit board 60 via the power supply current supply line 70 and the main power switch 50. Absent. Therefore, no direct current flows through the polarity switching start signal line 73 connected to the plus-side power supply current supply line 72 of the power supply current supply line 70.

  Therefore, the AC plug insertion / removal detection circuit 26 detects a change in the DC power supply current applied to the polarity switching start signal line 73 (S420 “changed”), and information that the AC plug 10 has been removed from the storage unit 24. Is stored (S430). Here, if the memory | storage part 24 is a non-volatile memory, a backup power supply or a battery (battery) is unnecessary. However, when the storage unit 24 is composed of a volatile memory or the like, power is supplied by a backup power source or a battery (battery). Note that the process of storing the information that the AC plug 10 has been removed to the storage unit 24 by the AC plug insertion / removal detection circuit 26 is performed by the polarity switching control from the AC plug insertion / removal detection circuit 26 after the AC plug 10 has been removed. Of course, it may be omitted if it can be directly notified to the circuit 22 '.

  Next, the AC plug 10 is connected to the outlet 104, and the electric device B is turned on. Then, the AC power supply current transformed by the internal transformer 30 is also supplied to the power supply circuit 40, and the main power switch 50 is turned on. As a result, a DC power supply current is also supplied from the power supply circuit 40 to the circuit board 60 via the power supply current supply line 70 and the main power supply switch 50.

  Then, the AC plug insertion / removal detection circuit 26 detects a change in the DC power supply current via the polarity switching start signal line 73 connected to the positive power supply current supply line 72 of the power supply current supply line 70 (S440 “changed”). The AC plug insertion / removal detection circuit 26 notifies the polarity switching control circuit 22 ′ that the AC plug 10 is connected to the outlet 104.

  The polarity switching control circuit 22 ′ is notified from the AC plug insertion / removal detection circuit 26 that the AC plug 10 is connected to the outlet 104. The polarity switching control circuit 22 'refers to the information that the AC plug 10 stored in the storage unit 24 has been removed, and the AC plug 10 is once removed while the main power switch 50 is turned on and then plugged again. Judge. Then, the polarity switching control circuit 22 'notifies the user that the polarity check of the AC power source is not performed by causing the notification unit 25 to output a warning display, a message display, or the like (S450).

  Then, the notification unit 25 prompts the user to turn on the electric device B from the main power switch 50 by a warning display, a message display, a warning sound, or the like. The user touches the human body contact portion 51 of the main power switch 50 by referring to the warning display, message display, warning sound, etc. of the notification portion 25. Thereby, the same process as the AC power supply polarity switching process of the first embodiment shown in FIG. 2 is executed, and the power supply polarity is automatically switched to the best state.

  This completes the polarity switching notification process when the AC plug 10 is inserted / removed in the AC power supply polarity switching device 20 of the second embodiment (S460).

Therefore, according to the AC power supply polarity switching device 20 of the second embodiment, the same effect as the AC power supply polarity switching device 20 of the first embodiment can be obtained. Further, after the AC power supply polarity is switched, when the AC plug 10 is inserted and removed while the main power switch 50 is on, the polarity is switched again for the user in the same manner as the AC power supply polarity switching device 20 of the first embodiment. Is notified to the user through the notification unit 25. In this way, by prompting the user to turn on the power again using the main power switch 50, the user is caused to execute the automatic switching of the power polarity again. Thereby, it is possible to prevent the electric device B from being turned on by a remote controller or the like while the AC plug 10 is pulled out and its direction is changed and the polarity of the AC power supply is not correct.
In the present embodiment, two polarity switching start signal lines 73 are provided so that it can be detected that the AC plug 10 has been removed even when the main power switch 50 remains on. The polarity switching start signal line 73 may be provided only in the plus-side power supply current supply line 72 between the power supply circuit and the constant voltage circuit. Since the AC plug 10 is often pulled out when the main power switch 50 is off, it is possible to detect that the AC plug 10 has been pulled out even with this configuration.

10 AC plug 20, 20 'Polarity switching control device 21 Polarity switching circuit (polarity switching unit)
22 Polarity switching control circuit (polarity switching control unit)
23 Voltage measurement circuit (Voltage measurement unit)
Reference Signs List 24 storage unit 25 notification unit 26 AC plug insertion / removal detection unit 30 internal transformer 40 power supply circuit 50 main power switch 51 human body contact unit 60 circuit board 70 power supply current supply line 71 power supply GND line (minus side power supply current supply line)
72 Positive power supply current supply line 73 Polarity switching start signal line 101 Transformer on pole 102 Power meter 103 No-fuse breaker 104 Outlet

Claims (4)

A power supply circuit that converts a current based on an input AC power supply current into a DC power supply current and supplies the current to a circuit board via a power supply current supply line and a main power switch;
A polarity switching unit that switches the polarity of the input AC power supply;
A voltage measuring unit for measuring a voltage between a power supply GND line of the power supply current supply line and a human body contact unit provided in the main power switch;
When the main power switch is turned on, a storage unit that stores the voltage measured by the voltage measurement unit;
After the storage unit stores the voltage measured by the voltage measurement unit, the polarity switching unit switches the polarity of the AC power supply, and then the voltage measurement unit causes the power supply of the power supply current supply line after the polarity switching. The voltage between the GND line and the human body contact part of the main power switch is measured, the magnitude of the voltage after the polarity switching is compared with the voltage before the polarity switching stored in the storage unit, and the memory Polarity switching for controlling the polarity switching of the AC power supply so that the polarity switching section switches the polarity of the AC power supply when the voltage before polarity switching stored in the unit is smaller than the voltage after the polarity switching A control unit;
An AC power supply polarity switching device characterized by comprising: The AC power supply polarity switching device according to claim 1,
An internal transformer for transforming the input AC power source to a power source voltage corresponding to the electrical device;
The AC power source polarity switching device, wherein the current converted by the power circuit is an AC power source current transformed by the internal transformer. In the alternating current power supply polarity switching device according to claim 1 or 2,
The polarity switching control unit
When performing control of polarity switching of the AC power supply, the user is informed through the notification unit that control of polarity switching of the AC power supply has been performed.
An AC power supply polarity switching device characterized by that. In the alternating current power supply polarity switching device according to any one of claims 1 to 3,
The AC power supply current that is input is an AC power supply current that is input from an AC plug that is plugged into an outlet.
An AC plug insertion / removal detection unit for detecting insertion / removal of the AC plug with respect to the outlet;
The polarity switching control unit
When it is detected by the AC plug insertion / removal detection unit that the AC plug has been removed from the outlet, and then it is detected that the AC plug has been inserted into the outlet, control of polarity switching of the AC power supply is executed. Notifying the user through the notification unit,
An AC power supply polarity switching device characterized by that.

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