JP2009278779A - Full-wave rectifying circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a full-wave rectifying circuit capable of preventing the deterioration due to arc discharge of relay contact points set on a power supply line of an AC power supply. <P>SOLUTION: The full-wave rectifying circuit includes a voltage synchronous signal generating circuit 11 for generating a synchronous signal synchronized with an AC voltage from an AC power supply 1, wherein a control circuit 10 opens and closes relay contact points 3a-1 and 3a-2 provided on the power supply line during a half-cycle period in which a current does not flow through the current line of a half-wave rectifying circuit L1 based on the synchronous signal, and opens and closes the relay contact points 3b-1, 3b-2 and 3c-1 provided on the power supply line during a half-cycle period in which a current does not flow through the current line of the half-wave rectifying circuit L2 based on the synchronous signal. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention synthesizes a voltage obtained by half-wave rectifying an AC voltage by two half-wave rectifier circuits connected to an AC power supply so as to have different rectification polarities, thereby generating a full-wave rectified voltage of the AC voltage. The present invention relates to a wave rectifier circuit.

  Conventionally, a half-wave rectification that generates a voltage obtained by full-wave rectifying the AC voltage by synthesizing a voltage obtained by half-wave rectifying the AC voltage by two half-wave rectification circuits connected to an AC power supply so as to have different rectification polarities. A synthetic-type full-wave rectifier circuit is known. This conventional half-wave rectification / synthesis full-wave rectification circuit will be described below with reference to the drawings.

  FIG. 9 is a configuration diagram of a conventional half-wave rectification / synthesis type full-wave rectification circuit. As shown in FIG. 9, the power supply line of the AC power supply 101 is branched to two half-wave rectifier circuits L100 and L200, and the two half-wave rectifier circuits L100 and L200 are such that the rectification polarities are opposite to each other. The AC power supply 101 is connected.

  This conventional full-wave rectifier circuit synthesizes a voltage obtained by half-wave rectifying the AC voltage from the AC power supply 101 by two half-wave rectifier circuits L100 and L200 connected to the AC power supply 101 so as to have different rectification polarities. Thus, a voltage obtained by full-wave rectifying the AC voltage from the AC power supply 101 is generated. A voltage obtained by synthesizing the half-wave rectified voltage is supplied to the load 103 via the power factor correction circuit 102.

  The power supply line of the AC power supply 101 further branches to the auxiliary power supply circuit 104. The auxiliary power supply circuit 104 converts the AC voltage from the AC power supply 101 into a DC voltage having a predetermined value, and controls the converted DC voltage. Supply to the circuit 105.

  The power supply line of the AC power supply 101 branched in the half-wave rectifier circuit L100 is connected to the input side terminal of the line filter 107a via relay contacts 106a-1 and 106a-2 driven by the relay drive circuit 106a. . Further, rectifier diodes 108a and 108b are connected to two terminals on the output side of the line filter 107a, respectively.

  The power supply line of the AC power supply 101 branched in the half-wave rectifier circuit L200 is connected to the input side terminal of the line filter 107b via relay contacts 106b-1 and 106b-2 driven by the relay drive circuit 106b. . Further, a current limiting resistor 109 is provided on one power supply line of the half-wave rectifier circuit L200, and a relay contact 106c-1 driven by the relay driving circuit 106c is connected in parallel with the current limiting resistor 109. Yes. Further, rectifier diodes 108c and 108d are connected to the two terminals on the output side of the line filter 107b, respectively.

  Half-wave rectification so that a voltage obtained by synthesizing voltages half-wave rectified by the two half-wave rectification circuits L100 and L200 configured as described above becomes a voltage obtained by full-wave rectification of the AC voltage from the AC power supply 101. The cathode of the rectifier diode 108a and the anode of the rectifier diode 108b of the circuit L100 are respectively connected to the cathode of the rectifier diode 108c and the anode of the rectifier diode 108d of the half-wave rectifier circuit L200, and the respective connection points are connected to the power factor improving circuit 102. Connected.

  The control circuit 105 controls the opening / closing driving of the relay contacts by the relay driving circuits 106a to 106c. That is, the control circuit 105 generates relay control signals for controlling the opening / closing driving of the relay contacts by the relay driving circuits 106a to 106c based on the ON / OFF signal input from the outside of the full-wave rectifier circuit.

  In addition, the control circuit 105 applies the DC voltage input from the auxiliary power supply circuit 104 as a relay drive voltage to a relay drive coil (not shown) included in the relay drive circuits 106a to 106c. The + 12V DC voltage from the auxiliary power circuit 104 is used as a relay driving voltage applied to the relay driving coil, and the + 5V DC voltage is used as an operating voltage other than the relay driving coil.

  Next, the operation of the full-wave rectifier circuit configured as described above will be described. When an ON signal is input to the control circuit 105 from the outside of the full-wave rectifier circuit, the control circuit 105 first operates the relay drive circuit 106b so that the relay contacts 106b-1 and 106b-2 are closed, and a half-wave. The smoothing capacitor 102c of the power factor correction circuit 102 is initially charged by the voltage from the rectifier circuit L200. During this initial charging, the current limiting resistor 109 limits the inrush current to the smoothing capacitor 102c. When the control circuit 105 recognizes the completion of the initial charging by measuring the charging time, the relay driving circuits 106a and 106c are operated so that the relay contacts 106a-1, 106a-2 and 106c-1 are closed, and this full-wave rectification is performed. The circuit is brought into a steady operation state (a state in which full wave rectification is executed).

  When an OFF signal is input to the control circuit 105 from the outside of the full-wave rectifier circuit, the control circuit 105 operates the relay drive circuits 106a to 106c so that all relay contacts are opened.

  Since the conventional half-wave rectification combined type full-wave rectifier circuit configured as described above has half the average current flowing through the relay contacts as compared to a normal full-wave rectifier circuit that handles full-wave AC voltage, Even when full-wave rectification is performed on large power, heat generation at the relay contacts can be reduced, which is advantageous in terms of safety.

  However, the conventional half-wave rectification combined type full-wave rectifier circuit opens and closes the relay contacts regardless of changes in the AC voltage to be rectified, so the relay contacts open and close when the maximum current near the peak of the AC voltage flows. As a result, arc discharge occurs between the contacts, which may cause contact deterioration and arc noise, which may shorten the life of the relay contacts. Therefore, in the conventional half-wave rectification combined type full-wave rectification circuit, a large-sized relay having a contact capacity more than necessary for the current flowing through the power supply line is used for the purpose of suppressing the life of the relay contact. As a result, miniaturization of the circuit was hindered. There were also problems of malfunction due to arc noise and interference with communication equipment.

  On the other hand, as a relay drive device with less relay contact deterioration and arc noise, an ON / OFF signal is sent to the transistor that turns the relay drive coil on / off, and then the relay contact provided on the AC power supply line opens and closes Means for measuring the time taken to operate (relay operating time) and means for generating a synchronizing signal synchronized with the AC voltage supplied from the AC power supply, thereby making the relay contact near the zero cross of the AC voltage. Has been proposed (see, for example, Patent Document 1).

However, in general, the operation time of the relay varies, and the operation time of the relay fluctuates due to temperature fluctuations. Therefore, in the conventional relay driving device described above, the operation time of the relay every time the relay driving device is used. It was necessary to measure. In addition, even if the relay operating time is measured, the relay operating time may fluctuate due to the temperature change of the relay driving coil in use, and there is also a bounce phenomenon where the contact opens when the relay closes, Since the zero crossing period of the AC voltage is extremely short, it is very difficult to accurately open and close the relay contacts near the zero crossing of the AC voltage.
JP 2001-84861 A

  In view of the above-described conventional problems, the present invention provides a half-wave rectifying / combining full-wave rectifier circuit in a half-cycle period in which no current flows in the power line of each half-wave rectifier circuit provided with contacts of each relay. By opening and closing the contact of each relay, the relay contact can be reliably performed in the zero current period even if the relay operation time varies or the relay operation time fluctuates due to temperature changes without measuring the relay operation time every time. It is an object of the present invention to provide a full-wave rectifier circuit that can open and close and prevent contact deterioration due to arc discharge, circuit malfunction due to arc noise, and interference with communication equipment.

  The full-wave rectifier circuit according to claim 1 of the present invention synthesizes a voltage obtained by half-wave rectifying the AC voltage from the AC power supply by two half-wave rectifier circuits connected to the AC power supply so as to have different rectification polarities. Thus, a full-wave rectifier circuit for generating a voltage obtained by full-wave rectifying the AC voltage, wherein at least one relay contact is provided on a power supply line connected to the AC power supply of each half-wave rectifier circuit. At least two relay drive circuits that open and close, a voltage synchronization signal generation circuit that generates a synchronization signal synchronized with the AC voltage, and a relay drive control unit that controls the opening and closing drive of the relay contacts by the relay drive circuits, respectively The relay drive control unit includes, based on the synchronization signal, the contact of each relay during a half cycle period in which no current flows through the power supply line provided with the contact of each relay. So you open and close, and controls the opening and closing of the contacts of the relay by the respective relay driving circuit, respectively.

  The full wave rectifier circuit according to claim 2 of the present invention is the full wave rectifier circuit according to claim 1, wherein the relay drive control unit recognizes the frequency of the AC voltage from the synchronization signal, and Signals for controlling the opening / closing drive of the relay contacts by the relay drive circuits are respectively generated at timings set according to the recognized frequencies.

  A full wave rectifier circuit according to claim 3 of the present invention is the full wave rectifier circuit according to any one of claims 1 and 2, wherein a relay drive voltage applied to a relay drive coil of the relay drive circuit is applied. A relay drive voltage control unit that switches between a plurality of set values is further provided.

  A full-wave rectifier circuit according to a fourth aspect of the present invention is the full-wave rectifier circuit according to any one of the first to third aspects, wherein the relay drive control unit is configured based on the synchronization signal. Each of the relay driving circuits controls the opening and closing of the relay contacts so that the relay contacts are closed at the front of a half-cycle period in which no current flows through the power supply line provided with the relay contacts. And

  According to a preferred embodiment of the present invention, the relay contact is reliably set in a zero current period even if there is a variation in the relay operation time or a change in the relay operation time due to a temperature change without measuring the relay operation time every time. It can be opened and closed, and contact deterioration due to arc discharge can be suppressed. Therefore, even when a large current is handled, the life of the relay contact can be extended. In addition, it is possible to prevent circuit malfunctions and interference with communication equipment due to arc noise.

  Hereinafter, embodiments of the full-wave rectifier circuit of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an outline of a configuration example of a half-wave rectification / synthesis type full-wave rectification circuit according to an embodiment of the present invention. As shown in FIG. 1, the power supply line of the AC power supply 1 is branched into two half-wave rectifier circuits L1 and L2, and the two half-wave rectifier circuits L1 and L2 are such that the rectification polarities are opposite to each other. Connected to AC power supply 1.

  This full-wave rectifier circuit synthesizes a voltage obtained by half-wave rectifying the AC voltage from the AC power supply 1 by two half-wave rectifier circuits L1 and L2 connected to the AC power supply 1 so as to have different rectification polarities. This is a half-wave rectification synthesis type full-wave rectification circuit that generates a voltage obtained by full-wave rectification of an AC voltage from the AC power supply 1, and a voltage obtained by synthesizing the half-wave rectified voltage is loaded via a power factor correction circuit 7 to a load 8 To supply.

  The power supply line of the AC power supply 1 further branches to the auxiliary power supply circuit 9. The auxiliary power supply circuit 9 converts the AC voltage from the AC power supply 1 into a DC voltage of a predetermined value, and controls the converted DC voltage. Supply to circuit 10. One power supply line of the AC power supply 1 is connected to the auxiliary power supply circuit 9 through the fuse 2e.

  Half-wave rectifier circuit L1 includes fuses 2a and 2b, relay drive circuit 3a, relay contacts 3a-1 and 3a-2, line filter 5a, and rectifier diodes 6a and 6b. One power supply line of the AC power supply 1 branched in the half-wave rectifier circuit L1 is connected to one terminal on the input side of the line filter 5a via the fuse 2a and the relay contact 3a-1, and the other power supply line Is connected to the other terminal on the input side of the line filter 5a via the fuse 2b and the relay contact 3a-2. Rectifier diodes 6a and 6b are connected to the two terminals on the output side of the line filter 5a, respectively. Relay drive circuit 3a opens and closes relay contacts 3a-1 and 3a-2 provided on the power line of half-wave rectifier circuit L1.

  Half-wave rectifier circuit L2 includes fuses 2c and 2d, relay drive circuit 3b, relay contacts 3b-1, 3b-2, relay drive circuit 3c, relay contact 3c-1, current limiting resistor 4, line filter 5b, and rectifier diode 6c. , 6d, and a voltage synchronization signal generation circuit 11.

  One power supply line of the AC power supply 1 branched in the half-wave rectifier circuit L2 is connected to one terminal on the input side of the line filter 5b via the fuse 2c and the relay contact 3b-1, and the other power supply line Is connected to the other terminal on the input side of the line filter 5b through the fuse 2d, the relay contact 3b-2, and the current limiting resistor 4. A relay contact 3c-1 is connected to the current limiting resistor 4 in parallel. Rectifier diodes 6c and 6d are connected to the two terminals on the output side of the line filter 5b. Relay drive circuit 3b opens and closes relay contacts 3b-1, 3b-2 provided on the power line of half-wave rectifier circuit L2. The relay drive circuit 3c opens and closes a relay contact 3c-1 that is connected in parallel to the current limiting resistor 4 provided in the power line of the half-wave rectifier circuit L2.

  The voltage synchronization signal generation circuit 11 is connected to the power supply line between the fuse 2c and the relay contact 3b-1 and the power supply line between the fuse 2d and the relay contact 3b-2, and is synchronized with the AC voltage from the AC power supply 1. Generate a synchronization signal.

  Half-wave rectification so that a voltage obtained by synthesizing voltages half-wave rectified by the two half-wave rectification circuits L1 and L2 configured as described above becomes a voltage obtained by full-wave rectification of the AC voltage from the AC power supply 1. The cathode of the rectifier diode 6a and the anode of the rectifier diode 6b of the circuit L1 are connected to the cathode of the rectifier diode 6c of the half-wave rectifier circuit L2 and the anode of the rectifier diode 6d, respectively. Connected.

  Based on the synchronization signal from the voltage synchronization signal generation circuit 11 and the ON / OFF signal from the outside of the full-wave rectification circuit, the control circuit 10 supplies power to each half-wave rectification circuit L1, L2 provided with each relay contact. The relay driving of the relay contacts by the relay drive circuits 3a to 3c is controlled so that the relay contacts are opened and closed during a half-cycle period in which no current flows through the line.

  Further, the control circuit 10 generates a relay drive voltage to be applied to a relay drive coil (not shown) included in the relay drive circuits 3a to 3c based on the DC voltage input from the auxiliary power supply circuit 9. Here, a case where +5 V and +15 V DC voltages are supplied from the auxiliary power supply circuit 9 to the control circuit 10 will be described. The + 15V DC voltage from the auxiliary power supply circuit 9 is used as a relay driving voltage applied to the relay driving coil, and the + 5V DC voltage is used as an operating voltage other than the relay driving coil.

  Next, an example of the configuration of the relay drive circuit 3b, the control circuit 10, and the voltage synchronization signal generation circuit 11 will be described with reference to FIG. FIG. 2 is a diagram showing an example of the configuration of the relay drive circuit 3b, the control circuit 10, and the voltage synchronization signal generation circuit 11 in the embodiment of the present invention.

  First, the voltage synchronization signal generation circuit 11 will be described. As shown in FIG. 2, the voltage synchronization signal generation circuit 11 includes resistors 12, 14, 16, a Zener diode 13, and a photocoupler 15.

  The resistor 12 and the Zener diode 13 are connected in series, one end of the resistor 12 is connected to the power line between the fuse 2c and the relay contact 3b-1, and the anode of the Zener diode 13 is connected between the fuse 2d and the relay contact 3b-2. Is connected to the power line. One end of the resistor 14 is connected to the connection point of the resistor 12 and the Zener diode 13 (the cathode of the Zener diode 13), and the other end is connected to the light emitting element of the photocoupler 15. Here, a case where the light emitting element is an LED will be described. The LED has an anode connected to the resistor 14 and a cathode connected to a power supply line between the fuse 2d and the relay contact 3b-2.

  On the other hand, the light receiving element of the photocoupler 15 is connected via a resistor 16 to a power supply line different from the power supply line branched from the AC power supply 1. Here, a case where the light receiving element is a phototransistor will be described. The input terminal of the phototransistor is connected to the + 5V power supply line via the resistor 16, and the output terminal is connected to the ground line.

  With this configuration, as shown in FIG. 3, the light-emitting element (LED) of the photocoupler 15 receives a drive voltage during a half-cycle period (here, a negative phase period) of the AC voltage supplied from the AC power supply 1. Since the voltage is applied, the light emitting element emits light during that period, and a half-cycle period (here, a negative phase) of the AC voltage supplied from the AC power supply 1 to the connection point between the resistor 16 and the light receiving element of the photocoupler 15. A rectangular synchronization signal whose signal level becomes LOW during the remaining half-cycle (here, the positive phase of the AC voltage supplied from the AC power supply 1) becomes HIGH. Occurs. Although the voltage synchronization signal generation circuit 11 is provided in the half-wave rectification circuit L2 here, it is needless to say that the voltage synchronization signal generation circuit 11 may be provided in the half-wave rectification circuit L1.

  Next, the control circuit 10 will be described. As shown in FIG. 2, the control circuit 10 includes a microcomputer 17 and a relay drive voltage switching circuit 18 that is a relay drive voltage control unit.

  The microcomputer 17 functioning as a relay drive control unit is based on the synchronization signal from the voltage synchronization signal generation circuit 11 and the ON / OFF signal from the outside of the full-wave rectifier circuit, and the relay contacts by the relay drive circuits 3a to 3c. The relay control signal for controlling the opening / closing drive of each is generated. Specifically, the signal level of the relay control signal input to each of the relay drive circuits 3a to 3c is set to a half cycle period in which no current flows through the power supply lines of the half-wave rectifier circuits L1 and L2 provided with the relay contacts. The transition is made so that each relay contact opens and closes.

  The relay drive voltage switching circuit 18 has a function of switching the relay drive voltage applied to the relay drive coils of the relay drive circuits 3a to 3c between a plurality of set values. Specifically, as the relay drive voltage, a + 15V DC voltage from the auxiliary power supply circuit 9 is directly applied to the relay drive coils of the relay drive circuits 3a to 3c, or a + 15V DC voltage from the auxiliary power supply circuit 9 is + 12V. And the converted +12 V DC voltage is applied to the relay drive coils of the relay drive circuits 3a to 3c. Here, the case where the maximum continuous applied voltage of relay drive circuits 3a to 3c is + 15V and the rated voltage is + 12V will be described as an example.

  Next, the relay drive circuit 3b will be described. As shown in FIG. 2, the relay drive circuit 3 b includes a transistor 19, resistors 20 and 21, a relay drive coil 22, and a free wheel diode 23.

  A relay control signal from the control circuit 10 (microcomputer 17) is input to the base of the transistor 19 via the resistor 20. The emitter of the transistor 19 is connected to the ground line, and the signal line connecting the base and the control circuit 10 is connected to the ground line via the resistor 21. A relay drive voltage from the control circuit 10 (relay drive voltage switching circuit 18) is applied to one end of the relay drive coil 22 that drives the relay contacts 3b-1, 3b-2, and the other end is connected to the collector of the transistor 19. is doing. The freewheel diode 23 is connected in parallel to the relay drive coil 22 in order to absorb a surge voltage generated in the relay drive coil 22.

  With this configuration, the relay contacts 3b-1 and 3b-2 are opened and closed according to the on / off operation of the transistor 19 according to the signal level of the relay control signal from the control circuit 10. Specifically, the relay contacts 3b-1, 3b-2 are opened when the signal level of the relay control signal is LOW, and are closed when the signal level of the relay control signal is HIGH. Although not shown, the relay drive circuits 3a and 3c can be configured similarly to the relay drive circuit 3b.

  In general, when the drive voltage is increased, the operation time of the relay is shortened and the variation is also reduced. In general, the operation time of the relay varies due to a change in ambient temperature. That is, the operating time is shortened at a low temperature where the DC resistance of the relay drive coil is small, and is increased at a high temperature. Explaining using the configuration shown in FIG. 2, the relay contacts 3b-1, 3b-2 are opened and closed after the signal level of the relay control signal from the microcomputer 17 changes from the LOW level to the HIGH level or from the HIGH level to the LOW level. The time until the operation (relay operating time) becomes shorter as the relay drive voltage from the relay drive voltage switching circuit 18 becomes higher, and becomes shorter at low temperatures and longer at high temperatures.

  Next, the operation of the full-wave rectifier circuit configured as described above will be described in detail. First, when power supply from the AC power supply 1 is started, + 5V and + 15V DC voltages converted in the auxiliary power supply circuit 9 are supplied to the control circuit 10 and the control circuit 10 is activated.

  The control circuit 10 first reads the falling timing of the synchronizing signal from the voltage synchronizing signal generation circuit 11, and based on the interval of the falling timing, the frequency of the AC voltage (power frequency) supplied from the AC power source 1 is 50 Hz. (Period: 20 ms) or 60 Hz (cycle: about 16.7 ms) is determined, and a delay time, which is a timing for changing the signal level of the relay control signal, is determined according to the recognized frequency (cycle). Set. By changing the signal level of the relay control signal at a timing delayed from the falling edge of the synchronization signal by the set delay time, a current does not flow in the power line of the half-wave rectifier circuit provided with the relay contact to be opened and closed. The relay contact can be opened and closed during the period of the cycle.

  The delay time includes a delay time when the relay contacts 3b-1, 3b-2 provided in the power line of the half-wave rectifier circuit L2 are closed, a delay time when the relay contacts 3b-1, 3b-2 are opened, and a power line of the half-wave rectifier circuit L2. The delay time when closing the relay contact 3c-1 and the delay time when opening the relay contact 3c-1, and the delay time when closing the relay contacts 3a-1 and 3a-2 provided on the power line of the half-wave rectifier circuit L1 and when opening Each relay contact is set according to the power supply frequency so as to open and close during a half-cycle period in which no current flows through the power supply line provided with each relay contact. Specifically, since the relay contact opens and closes at a timing delayed from the fall of the synchronization signal by the sum of the relay operation time and the delay time, the relay operation time is measured in advance, and the measured relay operation time The delay time for each power supply frequency is obtained based on the AC voltage cycle for each power supply frequency and stored in a storage unit (not shown) of this full-wave rectifier circuit. The circuit 10 may be configured to determine a delay time corresponding to the power supply frequency from the delay times stored in the storage unit.

  Thus, in this full-wave rectifier circuit, a signal for opening and closing the relay contact is generated at a timing set according to the frequency of the AC voltage from the AC power supply 1 (the signal level of the relay control signal is changed).

  Next, when an ON signal is input to the control circuit 10 from the outside of the full-wave rectifier circuit, the signal level of the relay control signal to each of the relay drive circuits 3a to 3c is set to LOW in accordance with the falling timing of the synchronization signal. Transition from level to HIGH level, respectively, closes the relay contact.

  Hereinafter, the operation when the relay contact is closed will be described in detail. FIG. 4 is a timing chart showing an example of the operation when closing the relay contacts of the full-wave rectifier circuit in the embodiment of the present invention. FIG. 5 is a timing chart for explaining the operation time of the relay when closing the relay contact in the embodiment of the present invention.

  4, in order from the top, a is the waveform of the AC voltage supplied from the AC power supply 1, b is the waveform of the current flowing through the power line of the half-wave rectifier circuit L1, and c is through the power line of the half-wave rectifier circuit L2. Waveform of current, d is the light emission timing of the light emitting element of the voltage synchronization signal generation circuit 11, e is the waveform of the synchronization signal generated in the voltage synchronization signal generation circuit 11, and f is input to the control circuit 10 from the outside of the full-wave rectification circuit The waveform of the ON / OFF signal to be generated, g is the waveform of the relay drive voltage generated in the control circuit 10, h is the waveform of the relay control signal transmitted from the control circuit 10 to the relay drive circuit 3b, and i is the relay contact 3b-1. 3b-2 closing timing, j is a waveform of a relay control signal transmitted from the control circuit 10 to the relay driving circuit 3c, k is a closing timing of the relay contact 3c-1, and 1 is a control circuit 10 Waveform of the relay control signal to be transmitted to Luo relay drive circuit 3a, m denotes a closing timing of the relay contacts 3a-1,3a-2. Here, a case will be described in which an ON signal / OFF signal for instructing opening / closing of a relay contact is generated by changing the signal level of the ON / OFF signal f.

  Further, t is a period of the AC voltage from the AC power source 1, t1 is a delay time when closing the relay contacts 3b-1, 3b-2, 3c-1 provided on the power line of the half-wave rectifier circuit L2, and t2 is a force. The initial charging time of the smoothing capacitor 7c of the rate improving circuit 7, t3 is the operation time of the relay, and t4 is the delay time when closing the relay contacts 3a-1 and 3a-2 provided on the power line of the half-wave rectifier circuit L1. .

  First, after the synchronization signal e synchronized with the AC voltage a supplied from the AC power supply 1 is input to the control circuit 10, the signal level of the ON / OFF signal f from the outside of the full-wave rectifier circuit transitions to the HIGH level. Then, the control circuit 10 switches the relay drive voltage g applied to the relay drive coil from the rated voltage 12V to the maximum continuous applied voltage 15V in order to reduce the variation in the relay operation time. As shown in FIG. 5, the operation time t3 of the relay when closing the relay contact is shorter and fluctuates when the relay drive voltage is 15V (maximum continuous applied voltage) than when the relay drive voltage is 12V (rated voltage). Becomes smaller. Here, the relay operation time t3 when the relay contact is closed is 7.6 ± 2.7 ms (variation: 5.4 ms) when the relay drive voltage is 15V, and 9.9 when the relay drive voltage is 12V. A case where the time is 6 ± 3.6 ms (variation: 7.2 ms) will be described as an example.

  Next, the control circuit 10 changes the signal level of the relay control signal h from the LOW level to the HIGH level at a timing delayed by a preset delay time t1 from the falling edge of the synchronizing signal e in accordance with the falling timing of the synchronizing signal e. The relay drive circuit 3b is operated so that the relay contacts 3b-1 and 3b-2 are closed, and the smoothing capacitor 7c of the power factor correction circuit 7 is initially charged by the voltage from the half-wave rectifier circuit L2. .

  At this time, the relay contacts 3b-1 and 3b-2 are closed at a timing delayed from the falling edge of the synchronization signal e by the sum of the relay operation time t3 and the delay time t1 ("h" and "i" in FIG. 4). See). Since the delay time t1 is set according to the power supply frequency, a half-cycle period (from the AC power supply 1 to the time when no current flows through the power supply line of the half-wave rectifier circuit L2 provided with the relay contacts 3b-1, 3b-2 is provided. The relay contacts 3b-1, 3b-2 can be closed during the positive phase of the AC voltage a) (see “a”, “c” and “i” in FIG. 4).

  During the initial charging of the smoothing capacitor 7c, the inrush current to the smoothing capacitor 7c is limited by the current limiting resistor 4. When the control circuit 10 recognizes the completion of the initial charging by measuring the charging time t2, the relay is performed at a timing delayed by a preset delay time t1 from the falling edge of the synchronizing signal e in accordance with the falling timing of the synchronizing signal e. After the relay drive circuit 3c is operated so that the relay contact 3c-1 is closed by changing the signal level of the control signal j from the LOW level to the HIGH level, a delay time set in advance from the same falling edge of the synchronization signal e By shifting the signal level of the relay control signal l from the LOW level to the HIGH level at a timing delayed by t4, the relay drive circuit 3a is operated so that the relay contacts 3a-1 and 3a-2 are closed, and this full-wave rectifier circuit Is in a steady operation state (a state in which full-wave rectification is executed).

  At this time, the relay contact 3c-1 is closed at a timing delayed from the fall of the synchronization signal e by the sum of the relay operating time t3 and the delay time t1 (see “j” and “k” in FIG. 4). . Since the delay time t1 is set in accordance with the power supply frequency, a half-cycle period (AC voltage a from the AC power supply 1) in which no current flows through the power supply line of the half-wave rectifier circuit L2 provided with the relay contact 3c-1. The relay contact 3c-1 can be closed during the positive phase (see “a”, “c” and “k” in FIG. 4).

  Further, the relay contacts 3a-1, 3a-2 are closed at a timing delayed from the falling edge of the synchronization signal e by the sum of the relay operating time t3 and the delay time t4 (“l” and “m” in FIG. 4 are closed). reference.). Since the delay time t4 is set according to the power supply frequency, a half-cycle period (from the AC power supply 1 to the time when no current flows through the power supply line of the half-wave rectifier circuit L1 provided with the relay contacts 3a-1, 3a-2. The relay contacts 3a-1 and 3a-2 can be closed during the negative phase of the AC voltage a (see “a”, “c”, and “m” in FIG. 4).

  Next, after all the relay contacts are closed, the control circuit 10 switches the relay drive voltage g applied to the relay drive coil from the maximum continuous applied voltage 15 V to the rated voltage 12 V, and generates heat and power consumption of the relay drive coil. Return to steady state.

  Although the case where the delay time when closing the relay contacts 3b-1 and 3b-2 and the delay time when closing the relay contact 3c-1 are the same time has been described here, the delay time is not limited to the same delay time. The relay contacts 3b-1, 3b-2, 3c-1 are closed during a period in which no current flows through the power line of the half-wave rectifier circuit L2 provided with the relay contacts 3b-1, 3b-2, 3c-1. I can do it. If charging of the smoothing capacitor 7c is completed and no current flows through the relay contacts 3b-1, 3b-2, 3c-1, the relay contacts 3b-1, 3b-2, 3c-1 are closed. The timing can be set arbitrarily. The delay time for closing the relay contacts 3a-1, 3a-2 is, for example, a time obtained by adding a half cycle time of the synchronization signal e to the delay time t1 for closing the relay contacts 3b-1, 3b-2. Should be set.

  Hereinafter, the delay time when closing the relay contact will be specifically described. Here, the half-cycle period of the current flowing through the power line of the half-wave rectifier circuit is 10 ms when the power frequency is 50 Hz, and approximately 8.3 ms when the power frequency is 60 Hz, and the variation in the operation time of the relay is 5.4 ms. (± 2.7 ms), and the half-cycle period of the current flowing through the power line of the half-wave rectifier circuit is longer than the variation in the operation time of the relay. For example, current flows through the power line of the half-wave rectifier circuit By setting the delay time so that the relay contact provided on the power supply line closes near the center of the half-cycle period, the relay contact can be reliably closed in the zero current period.

  For example, the delay time t1 for closing the relay contacts 3b-1, 3b-2 provided on the power line of the second half-wave rectifier circuit L2 is 7.4 ms when the power frequency is 50 Hz, and 60 Hz when the power frequency is 60 Hz. If set to 4.9 ms, the relay contacts 3b-1 and 3b-2 can be closed near the center of a half-cycle period in which no current flows through the power line of the half-wave rectifier circuit L2.

  In this case, even if there is a variation of ± 2.7 ms (5.4 ms) in the operation time of the relay, if the power supply frequency is 50 Hz, a half cycle in which no current flows in the power supply line of the half-wave rectifier circuit An operating margin of 2.3 ms is generated before and after this period, and an operating margin of about 1.45 ms is generated when the power supply frequency is 60 Hz.

  Also, considering the contact bounce phenomenon when the relay contact is closed, the relay contact closing timing is set to the front of a half-cycle period in which no current flows through the power line of the half-wave rectifier circuit. The operating margin may be increased. The case where the relay contact closing timing is set on the front side of the half cycle period will be described by taking the relay contacts 3b-1 and 3b-2 as an example.

  FIG. 6 is a diagram for explaining the closing timing of the relay contacts 3b-1 and 3b-2. FIG. 6A shows the waveform of the current flowing through the power supply line of the half-wave rectifier circuit L2. Enlarged views of the waveforms are shown in FIGS. 6 (b) and 6 (c). FIG. 6B shows the closing timing when the relay contacts 3b-1 and 3b-2 are closed near the center of the half-cycle period in which no current flows through the power line of the half-wave rectifier circuit L2. c) shows the closing timing when the relay contacts 3b-1 and 3b-2 are closed on the front side of a half-cycle period in which no current flows through the power line of the half-wave rectifier circuit L2. Here, a case where the power supply frequency is 60 Hz will be described as an example.

  As shown in FIG. 6, when the power supply frequency is 60 Hz, the half cycle of the current flowing through the power line of the half-wave rectifier circuit L2 is about 8.3 ms, and the relay contact 3b-1 near the center of the half cycle period, When 3b-2 is closed, as shown in FIG. 6 (b), since the variation in the operation time of the relay is 5.4 ms, an operation margin of about 1.45 ms is generated before and after.

  On the other hand, for example, as shown in FIG. 6C, when the closing timing of the relay contacts 3b-1, 3b-2 is set so that the operation margin on the front side is 1 ms, the operation margin on the rear side is about The bounce generated when the relay contacts 3b-1 and 3b-2 are closed can be absorbed during a period in which no current flows through the power line of the half-wave rectifier circuit L2. When the power supply frequency is 50 Hz and the relay contact closing timing is set so that the operation margin on the front side is 1 ms, the operation margin on the rear side is 3.6 ms.

  Next, the operation of the full-wave rectifier circuit when an OFF signal is input to the control circuit 10 from the outside of the full-wave rectifier circuit will be described. When an OFF signal is input from outside the full-wave rectifier circuit to the control circuit 10, the control circuit 10 sets the signal level of the relay control signal to each of the relay drive circuits 3a to 3c in accordance with the falling timing of the synchronization signal. Are shifted from HIGH level to LOW level, and the relay drive circuits 3a to 3c are operated so that all relay contacts are opened.

  Hereinafter, the operation when the relay contact is opened will be described in detail. FIG. 7 is a timing chart showing an example of the operation when opening the relay contacts of the full-wave rectifier circuit in the embodiment of the present invention. FIG. 8 is a timing chart for explaining the operation time of the relay when the relay contact is opened in the embodiment of the present invention.

  In FIG. 7, in order from the top, a is a waveform of an AC voltage supplied from the AC power supply 1, b is a waveform of a current flowing through the power line of the half-wave rectifier circuit L1, and c is a power line of the half-wave rectifier circuit L2. Waveform of current, d is the light emission timing of the light emitting element of the voltage synchronization signal generation circuit 11, e is the waveform of the synchronization signal generated in the voltage synchronization signal generation circuit 11, and f is input to the control circuit 10 from the outside of the full-wave rectification circuit The waveform of the ON / OFF signal to be generated, g is the waveform of the relay drive voltage generated in the control circuit 10, h is the waveform of the relay control signal transmitted from the control circuit 10 to the relay drive circuit 3b, and i is the relay contact 3b-1. 3b-2 opening timing, j is a waveform of a relay control signal transmitted from the control circuit 10 to the relay driving circuit 3c, k is an opening timing of the relay contact 3c-1, and l is a control circuit 10 Waveform of the relay control signal to be transmitted to Luo relay drive circuit 3a, m denotes a timing of opening the relay contacts 3a-1,3a-2. Here, a case will be described in which an ON signal / OFF signal for instructing opening / closing of a relay contact is generated by changing the signal level of the ON / OFF signal f.

  T is the period of the AC voltage from the AC power supply 1, t5 is the delay time when opening the relay contacts 3b-1, 3b-2 provided on the power line of the half-wave rectifier circuit L2, and t6 is the operation time of the relay. , T7 is a delay time when the relay contact 3c-1 provided in the power line of the half-wave rectifier circuit L2 is opened, and t8 is a relay contact 3a-1, 3a-2 provided in the power line of the half-wave rectifier circuit L1. This is the delay time when opening. Here, the delay time t5 when opening the relay contacts 3b-1 and 3b-2 and the delay time t7 when opening the relay contact 3c-1 are set to the same time.

  The operation time t6 of the relay when opening the relay contact is generated due to the return current by the surge absorbing freewheel diode 23 connected in parallel to the relay drive coil. Here, as shown in FIG. 8, a case where the operation time t6 of the relay is 10.8 ± 1.8 ms (variation: 3.6 ms) will be described as an example.

  When the signal level of the ON / OFF signal f from the outside of the full-wave rectifier circuit transitions to the LOW level, the control circuit 10 first starts from the falling edge of the synchronizing signal e in accordance with the falling timing of the synchronizing signal e. The relay contacts 3b-1, 3b-2 and 3c-1 are opened by changing the signal level of the relay control signals h and j from the HIGH level to the LOW level at a timing delayed by the set delay time t5 (t7). After the relay drive circuits 3b and 3c are operated, at a timing delayed by a preset delay time t8 from the same falling edge of the synchronization signal e, that is, half of the synchronization signal e from the transition timing of the signal level of the relay control signals h and j. By changing the signal level of the relay control signal 1 from HIGH level to LOW level at the timing after the period of the cycle, By operating the relay drive circuit 3a to open it over the contacts 3a-1, 3a-2, open all the relay contacts.

  At this time, the relay contacts 3b-1, 3b-2, 3c-1 are opened at a timing delayed from the falling edge of the synchronization signal e by the sum of the relay operation time t6 and the delay time t5 (t7) (see FIG. 7). (See “h”, “i”, “j” and “k”.) Since the delay time t5 (t7) is set according to the power supply frequency, a half cycle in which no current flows through the power supply line of the half-wave rectifier circuit L2 provided with the relay contacts 3b-1, 3b-2, 3c-1 is provided. The relay contacts 3b-1, 3b-2, 3c-1 can be opened during the period (the period of the positive phase of the AC voltage a from the AC power supply 1) ("a", "c", " i "and" k ").

  Also, the relay contacts 3a-1, 3a-2 are opened at a timing delayed from the falling edge of the synchronization signal e by the sum of the relay operation time t6 and the delay time t8 ("l" and "m" in FIG. 4 are opened). reference.). Since the delay time t8 is set in accordance with the power supply frequency, a half-cycle period (from the AC power supply 1) that current does not flow through the power supply line of the half-wave rectifier circuit L1 provided with the relay contacts 3a-1, 3a-2. The relay contacts 3a-1, 3a-2 can be opened during the negative phase of the AC voltage a (see “a”, “c”, and “m” in FIG. 4).

  Hereinafter, the delay time when opening the relay contact will be described. Here, the period of the half cycle of the current flowing through the power line of the half-wave rectifier circuit is 10 ms when the power frequency is 50 Hz and about 8.3 ms when the power frequency is 60 Hz, and the variation in the relay operation time is 3.6 ms. (± 1.8 ms), and the half-cycle period of the current flowing through the power supply line of the half-wave rectifier circuit is longer than the variation in the operation time of the relay. Also, there is no bounce phenomenon when opening the relay contacts. Thus, for example, if the delay time is set so that the relay contact provided in the power supply line opens near the center of the half-cycle period in which no current flows in the power supply line of the half-wave rectifier circuit, the relay contact is It can be opened reliably.

  Specifically, the delay time t5 (t7) when opening the relay contacts 3b-1, 3b-2, 3c-1 provided on the power supply line of the half-wave rectifier circuit L2 is 4 when the power supply frequency is 50 Hz. In the case of .2 ms and 60 Hz, if set to 1.7 ms, the relay contacts 3b-1, 3b-2, 3c-1 near the center of the half-cycle period in which no current flows through the power line of the half-wave rectifier circuit L2. Can be opened. The delay time t8 when opening the relay contacts 3a-1, 3a-2 provided on the power line of the half-wave rectifier circuit L1 is 14.2 ms when the power frequency is 50 Hz, and 10 ms when the power frequency is 60 Hz. If set, the relay contacts 3a-1 and 3a-2 can be opened near the center of a half-cycle period in which no current flows through the power line of the half-wave rectifier circuit L1.

  In addition, although the case where the delay time t5 when opening the relay contacts 3b-1 and 3b-2 and the delay time t7 when opening the relay contact 3c-1 are the same time has been described here, the present invention is not limited thereto. If the delay time t7 is equal to or greater than the delay time t5, no current flows through the relay contact 3c-1 after the relay contacts 3b-1 and 3b-2 are opened. Therefore, if the delay time t7 is equal to or greater than the delay time t5. Good.

  In addition, the opening timing of the relay contact is not limited to the case where it is set near the center of the period in which no current flows in the power line provided with the relay contact, but in the period in which no current flows in the power line provided with the relay contact. Just open the relay contact.

  The full-wave rectifier circuit according to the present invention can open and close the relay contact provided in the power supply line during the zero current period of each half-wave rectifier circuit, suppress contact deterioration due to arc discharge, and handle all currents. Useful for wave rectifier circuits.

The figure which shows the outline of one structural example of the half wave rectification synthetic | combination type full wave rectifier circuit in embodiment of this invention The figure which shows an example of a structure of the relay drive circuit in the embodiment of this invention, a control circuit, and a voltage synchronous signal generation circuit Timing chart for explaining the operation of the voltage synchronization signal generating circuit in the embodiment of the present invention The timing chart figure which shows an example of the operation | movement at the time of closing the relay contact of the full wave rectifier circuit in embodiment of this invention The timing chart for demonstrating the operation time of the relay at the time of closing the relay contact in embodiment of this invention The figure for demonstrating the closing timing of the relay contact in embodiment of this invention The timing chart figure which shows an example of the operation | movement at the time of opening the relay contact of the full wave rectifier circuit in embodiment of this invention Timing chart for explaining the operation time of the relay when opening the relay contact in the embodiment of the present invention Configuration diagram of a conventional half-wave rectification synthesis type full-wave rectification circuit

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 AC power source 2a-2e Fuse 3a-3c Relay drive circuit 3a-1, 3a-2 Relay contact 3b-1, 3b-2 Relay contact 3c-1 Relay contact 4 Current limiting resistance 5a, 5b Line filter 6a-6d Rectifier diode 7 Power Factor Correction Circuit 7c Smoothing Capacitor 8 Load 9 Auxiliary Power Supply Circuit 10 Control Circuit 11 Voltage Synchronous Signal Generation Circuit 12 Resistor 13 Zener Diode 14 Resistor 15 Photocoupler 16 Resistor 17 Microcomputer 18 Relay Drive Voltage Switching Circuit 19 Transistor 20 Resistor 21 Resistor 22 Relay drive coil 23 Freewheel diode L1, L2 Half-wave rectifier circuit 101 AC power supply 102 Power factor improvement circuit 102c Smoothing capacitor 103 Load 104 Auxiliary power supply circuit 105 Control circuit 106a-106c Relay drive circuit 106a-1,106a-2 relay contacts 106b-1,106b-2 relay contacts 106c-1 relay contacts 107a, 107b line filter 108a~108d rectifier diode 109 current limiting resistor L100, L200 half-wave rectifier circuit

Claims (4)

A voltage obtained by full-wave rectifying the AC voltage is generated by synthesizing a voltage obtained by half-wave rectifying the AC voltage from the AC power supply by two half-wave rectifier circuits connected to the AC power supply so as to have different rectification polarities. A full wave rectifier circuit,
At least two relay driving circuits that respectively open and close contact points of relays provided in at least one power supply line connected to the AC power supply of each half-wave rectifier circuit;
A voltage synchronization signal generating circuit for generating a synchronization signal synchronized with the AC voltage;
A relay drive control unit for controlling the opening and closing drive of the contact of the relay by each relay drive circuit;
And the relay drive control unit is configured to open and close the relay contacts based on the synchronization signal so that the relay contacts open and close during a half-cycle period in which no current flows through the power supply line provided with the relay contacts. A full-wave rectifier circuit that controls the opening / closing drive of the relay contacts by the drive circuit.   The relay drive control unit recognizes the frequency of the AC voltage from the synchronization signal, and at each of the timings set according to the recognized frequency, signals for controlling the opening / closing drive of the relay contacts by the relay drive circuits, respectively. The full-wave rectifier circuit according to claim 1, wherein the full-wave rectifier circuit is generated.   3. The full-wave rectification according to claim 1, further comprising a relay drive voltage control unit that switches a relay drive voltage applied to a relay drive coil of the relay drive circuit between a plurality of set values. circuit.   The relay drive control unit, based on the synchronization signal, drives each relay so that the contact of each relay is closed at the front of a half-cycle period in which no current flows through the power supply line provided with the contact of each relay. 4. The full-wave rectifier circuit according to claim 1, wherein the switching driving of the relay contacts by the circuit is controlled.

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